Crystallization and preliminary crystallographic investigations of cytochrome c4 from Pseudomonas stutzeri

Cytochrome c(4) from the bacterium Pseudomonas stutzeri has been crystallized and X-ray diffraction data have been collected to 2.2 A resolution. The crystals belong to the monoclinic system, space group P2(1) with cell parameters a = 49.49, b = 58.58, c = 63.51 A and beta = 96.96 degrees. The crystals contain two molecules it, the asymmetric unit. Cytochrome c(4) is known to contain two covalently bound haem groups per molecule and positions of the four haem Fe atoms in the asymmetric unit were determined from native anomalous-dispersion differences. The shortest Fe-Fe distances found in the crystal were 15.8, 16.9 and 19.0 A.